WO2018122255A1

WO2018122255A1 - Electromagnetic assembly of polyphase structure

Info

Publication number: WO2018122255A1
Application number: PCT/EP2017/084633
Authority: WO
Inventors: François BERNOT
Original assignee: Francecol Technology; Zodiac Actuation Systems; Mbda France
Priority date: 2016-12-27
Filing date: 2017-12-27
Publication date: 2018-07-05
Also published as: JP2020515216A; EP3563468A1; CN110383635A; FR3061370B1; US11196307B2; FR3061370A1; US20200006992A1

Abstract

The present invention relates to an electromagnetic assembly (1) of polyphase structure, said assembly including: a yoke (5) comprising an electromagnetic body; a plurality of spaced-apart blocks (50) that protrude with respect to one of the carrier faces (5A, 5B) of the yoke (5) and that are arranged, consecutively, along the periphery of the carrier face (5A, 5B) of the yoke (5); and at least one winding (6) that is associated with the blocks (50), wherein there is only one yoke (5), the plurality of blocks (50) is arranged in at least two groups of blocks (A, B, C) in which two consecutive blocks (50) of a given group of blocks (A, B, C) are spaced apart by an inter-block distance (E), and each group of blocks (A, B, C) is separated from the adjacent group of blocks (A, B, C) by an inter-group distance (D) that is different from the inter-block distance (E).

Description

ELECTROMAGNETIC ASSEMBLY WITH POLYPHASE STRUCTURE

The present invention relates to an electromagnetic assembly with polyphase structure with winding. The term polyphase structure with respect to the electromagnetic assembly with winding, an electromagnetic assembly with winding whose number of phases is greater than one.

More specifically, the present invention will be described with regard to a use of such an electromagnetic assembly as a stator or rotor of an electric motor, in particular having a motor and / or generator operating mode, without however being limited thereto.

The present invention is applicable to any use of such an electromagnetic assembly in an electrical rotating machine, other than a motor, and to any rotating device using an electromagnetic yoke having the features of the present invention.

For example, the present invention also finds application in the field of position sensors, speed sensors or acceleration sensors. In known manner, an electromagnetic yoke is most often cylindrical, solid or hollow, extending along a longitudinal axis (said z axis), and comprises an alternation of magnetic poles salient, consisting of an alternation of studs (or teeth ) and notches, the studs projecting from the inner or outer face of the body of the electromagnetic yoke and equidistant.

In addition, it is known a single-phase electromagnetic cylinder head having a single coil extending from an inlet power supply to a power supply output and wound around each pad, said magnetic, to create an incoming flow and a flow out alternately between the successive pads and equidistant. The winding can be performed in a wavy manner, that is to say passing from one pad to another by changing the face of each pad, or nested, that is to say by completely surrounding each pad. The winding is at one or more turns.

The electromagnetic yoke with a single-phase structure thus produced is intended to be placed opposite an electromagnetic element, for example composed of magnets, and at a distance from it to provide an electromagnetic air gap surface.

To manufacture a polyphase electrical machine, assembling, as illustrated in Figure 1, several electromagnetic heads with single-phase structure C1 to C3, as described above, stacked along the z axis. Each electromagnetic cylinder head C1 to C3 single-phase structure is provided with a plurality of P-pads equidistant on the periphery of the electromagnetic cylinder head and form with its associated winding a phase. By assembling three electromagnetic heads, the assembly thus formed forms a three-phase structure. It is desired that the respective windings electromagnetic heads single phase structure are not in contact in order to avoid any short circuit. Also, by stacking the electromagnetic heads with their winding, care is taken to separate them from each other to prevent them from touching each other. In addition, the electromagnetic heads are arranged between them so as to ensure an angular offset between the studs of two consecutive electromagnetic heads. Such an angular offset is equal to

360 (2 ^* Np ^* Nphases), where Np is the number of magnetic poles, and Nphases, the number of electromagnetic heads with single-phase structure (also called number of phases).

In an electric motor, it is always desired to increase the number of phases, beyond the unit, which allows starting of the electric motor, or to improve an electrical form factor of the electric motor to reduce that the couple is drawn too much.

This is generally achieved by assembling a plurality of single-phase electromagnetic heads. However, such an assembly increases the size of the motor along the z axis, since it is necessary to space between them single-phase wire electromagnetic cylinder coils. In particular, each added phase increases the initial length of the engine in order, in particular, to preserve a space between each electromagnetic bolt. However, in some applications, congestion can be problematic and it is thus sought to provide polyphase motors of the smallest possible volume.

In addition, there are difficulties in the design and maintenance of such an assembly of a plurality of electromagnetic assemblies with a single-phase structure.

Finally, the manufacturing cost of such an engine is quickly high.

The present invention therefore aims to provide an electromagnetic assembly with a polyphase structure does not have the aforementioned drawbacks. It aims in particular to minimize the volume occupied by such a set. The present invention also has the advantage, through its use in an electric motor, to allow an increase in engine torque without affecting the bulk. Other advantages of the polyphase electromagnetic assembly of the present invention will be detailed in the description which follows. According to the present invention, the electromagnetic assembly with a polyphase structure comprises a yoke having an electromagnetic body and a plurality of spaced studs projecting from a support face of the yoke, this support face of the yoke being advantageously one of the faces of the cylinder head, and arranged consecutively along the periphery of the support face of the cylinder head, and a coil associated with the pads. In addition, the cylinder head is unique, that is to say that the assembly has only one cylinder head, and the plurality of pads is arranged in at least two groups of pads in which two consecutive pads of the same group of pads are spaced apart from one inter-pad distance and each pad group is separated from the adjacent pad group by an intergroup distance distinct from the pad distance.

Advantageously, a winding is associated with each group of pads.

By "adjacent group" is meant the group of pads that follows immediately after a group of pads with regard to the consecutive arrangement of the pads and groups of pads.

Depending on the structure of the cylinder head, the pads may have different shapes and sizes.

Preferably, the studs of the cylinder head all have the same shape.

The geometric shape of a stud may vary depending on the yoke and the intended application, the intergroup distance is considered as the angular distance separating the median axes perpendicular to the support face of two consecutive studs belonging to two adjacent groups. The inter-plot distance is considered as the angular distance separating the median axes perpendicular to the support face, of two consecutive pads belonging to the same group. According to one characteristic, the body of the cylinder head is annular, or cylindrical in one or two annular parts, or cylindrical abutments, in particular along the longitudinal axis of the cylinder, or discoidal, or parallelepiped. If the magnetic yoke has a disc-shaped or annular body, the support surface from which the studs project is of preferably circular geometry. In addition, the pads are arranged consecutively along the circular periphery of the support face. However, other geometries are possible for the studs, in particular frustoconical studs.

If the magnetic yoke is of linear shape, that is to say that it is in a parallelepipedal shape, the pads are arranged consecutively along a right side of the cylinder head.

Thus, on the same surface and via a single cylinder head, it is possible to obtain an electromagnetic assembly with a polyphase structure without having, as in the prior art, successively stacked along the z-axis several electromagnetic heads. In addition, it is possible to get rid of the space separating two successive yokes.

Consequently, the present invention makes it possible to produce an electromagnetic assembly with a polyphase structure, compact and reduced in size along the z axis. In the end, the present invention advantageously allows a reduction in the overall size of an electromagnetic assembly with a polyphase structure.

In the remainder of the description, whatever the shape of the yoke, the axis z is understood by the axis which corresponds to the axis in which it would be necessary to stack axially several yokes with a single-phase structure if the entire The invention did not propose the particularity of arrangement of the electromagnetic pads. The z axis is also perpendicular to the magnetic flux induced in the air gap provided when another electromagnetic element is placed opposite and at a distance from the electromagnetic studs, and an electric current is applied to the winding. For an annular or discoidal yoke, the z axis is perpendicular to the radial plane. For a parallelepipedic bolt, also called linear, the z axis is perpendicular to the longitudinal direction of the studs.

For a cylinder head in at least two annular or cylindrical abutment parts, each part comprises a respective number of studs spaced apart so that between two consecutive studs of a part, the space allows to receive a stud of a other part. The studs of the annular or abutting cylindrical portions are thus associated head-to-tail and parallel to each other while respecting the intergroup and inter-plot distances claimed. The term "coil associated with each group of pads" in the following description, a coil having a power supply input and a power supply output for each group of pads or for each combination of subgroups. A combination of subgroups is defined below. The group configuration of the pads, combined with an intergroup distance distinct from the inter-pad distance, allows, when the coil is electrically powered, to provide a plurality of electrical phases with an electrical offset between the phases, providing an electromagnetic assembly with a structure polyphase. Therefore, the electromagnetic assembly with a polyphase structure is according to the present invention of "monoblock" type by compacting the phases in a single annular, discoidal or parallelepipedic volume, without the need to stack a plurality of electromagnetic heads in parallel consecutive planes. and spaced. We hear by "Monobloc", the fact that the electromagnetic assembly with a polyphase structure comprises only one cylinder head forming with the groups of pads a unit mass.

The polyphase structure is obtained from a single cylinder head. The unit mass of the electromagnetic assembly of the invention provides a polyphase structure with a smaller footprint than that which would be necessary for a set of the prior art for which the polyphase structure is obtained by stacking and spacing several yokes with a single-phase structure. . Such a one-piece design of the electromagnetic assembly with a polyphase structure has additional and / or alternative advantages to that of a reduced space requirement, in particular:

it is possible to concentrate the same number of phases in a smaller space and to provide an axial length which makes it possible to increase the torque of the motor;

the volume of the winding is reduced, and thus a reduction in the amount of electric wire, generally made of copper, is achieved, which also reduces the manufacturing costs;

the length of the electric wire of the total winding is reduced for all the phases, and thus it is possible to reduce the electrical resistance, and consequently to reduce the losses by Joule effect;

an arrangement of the pads is defined such that the latter are no longer equidistant over the entire circumference, involving an angular offset with the other magnetic element intended to be positioned facing each other, for example a rotor if the assembly The electromagnetic device of the invention is a stator, and thus it is possible to reduce the engine holding torque (generally qualified by the Anglicism "Cogging") and thus facilitates the rotational launch of the rotor; maintenance of the electromagnetic assembly, and thus it is possible to facilitate maintenance of the electric motor incorporating such an electromagnetic assembly;

- The assembly and disassembly of the electromagnetic assembly with polyphase structure are easy;

- manufacturing costs are reduced;

- the risks of wear due to vibrations for high speed motors are reduced.

According to another characteristic, the electromagnetic assembly with a polyphase structure comprises several phases so that each phase of the electromagnetic assembly with polyphase structure corresponds to

either at each of the groups of pads, the groups being considered consecutively and a separate winding being associated with each group,

or at least two remote groups (two groups not following each other consecutively) associated with the same separate winding of the winding of the other groups.

The combination of at least two remote groups associated with the same winding is defined in the invention as subgroups. When the yoke is annular or discoidal and two subgroups constitute a phase, the two subgroups are arranged diametrically opposite.

When the yoke is parallelepiped and two subgroups constitute a phase, the two subgroups are arranged on either side of the first group of phases formed of subgroups.

When the electromagnetic assembly with polyphase structure preferably comprises groups of studs divided into subgroups as mentioned above, the intergroup distance defined above and corresponding to two adjacent groups remains the same. Thus, the intergroup distance is also the distance separating an end pad, along the median axis perpendicular to the support face, of a first subgroup of a group, from the pad immediately after, along the median axis perpendicular to the support face, the subgroup of another group arranged adjacent to the first group.

According to a particular embodiment, the intergroup distances are identical over the entire cylinder head.

When each of the intergroup distances is the same over the entire periphery of the cylinder head, it is substantially equal to an electric angle corresponding to

- 180 Nphases, when the number of phases is odd, and

- 360 Nphases, when the number of phases is even,

where Nphases is the number of phases, in particular considering that the inter-plot distance of each group or each subgroup is identical and is equal to 180 ° electrical.

An electrical angle is defined as being equal to a full mechanical revolution, ie 360 ° divided by the number of pole pairs. When the structure is linear, the electrical angle is defined as having a value equal to 360 ° to the distance separating two pairs of consecutive poles.

Thus, preferably, the groups or subgroups of pads are distributed in a balanced manner, according to an equidistance between each group or subgroup, on the surface of the cylinder head, the intergroup distance is therefore identical. Such an arrangement makes it possible to obtain a balance of the radial electric forces for an electromagnetic assembly with an annular or discoidal yoke.

Preferably, according to the intended application, in particular for an engine, the number of subgroups of pads is preferably an even number and / or the number of groups corresponding to the number of phases is preferably an odd number.

By way of example, the electromagnetic assembly with a polyphase structure has a three-phase structure and comprises

- three groups of pads, each group corresponding to a phase,

or three pairs of subgroups of pads, each pair of subgroups corresponding to one phase and the two subgroups of each pair being arranged diametrically opposite and associated with the same coil.

In another embodiment, the electromagnetic assembly with a polyphase structure has a five-phase structure and comprises five groups of pads each associated with a separate winding.

According to a preferred characteristic, each group of pads or subgroups comprises an identical number of pads, either odd or even.

The electromagnetic assembly with a multiphase structure comprises a coil by group of pads or by combination of subgroups, such as in particular in pairs, each coil being formed by one or more turns associated with each of the pads. The windings of the groups can be connected in series or in parallel, or in any other way.

A winding can be realized

in a wavy manner, that is to say passing from one pad to another, alternately passing from one pole face of a pad to an opposite polar face for the next pad, or

- nested way by completely surrounding each of the pads.

In known manner polar faces, the faces of the pads extending in planes perpendicular to the z axis. In a particular embodiment, some pads are not wound, or receive a double coil.

Advantageously, the coils are intended to be electrically powered by a polyphase balanced current. However, the current may not be balanced.

Preferably, the current supplying the winding of each group or combination of subgroups for each phase is wedged angularly with respect to the phase shift between the phases.

Moreover, the current flowing through each winding can be sinusoidal, triangular, rectangular, in particular rectangular with three levels, etc.

By way of nonlimiting examples, the pads may have various shapes, such as a cylindrical shape with a circular or polygonal base, or a mushroom shape, or a flared solid shape preferably diverging towards the opposite side of the face. support, and / or a solid shape having on at least one of the pole faces a recess, preferably having a single recess such that each recess of two consecutive pads is alternately disposed on each polar face, in particular to associate the coil of wavy way.

Preferably, the pads of the same electromagnetic assembly with a polyphase structure have the same shape.

According to yet another feature, one or more pads are removably reported against the yoke, in particular by interlocking with or without play, and / or bonding and / or by an interface element and securing. In particular, the pads may have a base intended to cooperate with the support face in a dovetail-shaped cooperation.

In particular, each stud has a surface opposite to the support face of the yoke and intended to face an air gap, having a convex shape, so as to provide a gap of varying distance. Such geometry allows the induced voltage to be sinusoidal.

The present invention also relates to a device comprising such an electromagnetic assembly with a polyphase structure and an electromagnetic element placed opposite the gap, such as with magnets, arranged vis-a-vis and at a distance to arrange between the element and the assembly, a gap.

In other alternative embodiments of the present invention, it is possible to place opposite the electromagnetic assembly with a polyphase structure, opposite the gap, a set of magnetic shims concentrating the flux of magnets, or a cage substantially similar to that of cage induction motors, or a set of short-circuited coils, or a single-phase or multiphase wound armature, or a non-coiled frame as used in variable reluctance machines, comprising a number of teeth, which armature comprises a number of poles distributed substantially equal to the periphery of the air gap, 180 electrical apart from each other

When the yoke of the electromagnetic assembly with polyphase structure is cylindrical, the studs protrude from the cylindrical surface is internal or external. In a use with an electromagnetic element opposite and spaced apart, the cylinder head will then be respectively said external and arranged around the electromagnetic element, or said internal with the electromagnetic element arranged around.

When the yoke of the electromagnetic assembly with polyphase structure is discoidal or parallelepipedic (or linear) for an electric motor application, the cylinder head will be arranged either on the right or on the left. In an alternative embodiment of the present, it is possible that the phases do not have the same number of pads. In a particular configuration, it is possible that the subgroups of pads do not all have the same number of pads. Depending on the application and the embodiment of the electromagnetic element associated with the electromagnetic assembly with polyphase structure of the invention, the cylinder head will be either fixed or rotating.

The present invention also relates to a machine comprising the electromagnetic assembly with a polyphase structure of the invention, such as a rotating or static electrical machine, in particular a DC, synchronous magnet, synchronous wound-rotor, asynchronous-to-synchronous machine. squirrel cage rotor, asynchronous rotor wound, stepwise (so-called variable reluctance), an electric motor, an alternator, a starter, a retarder, a position sensor, a speed sensor, an acceleration sensor , or any other application.

The present invention also applies to a fixed or movable armature, placed inside or outside the armature vis-à-vis, or right or left of it. The frame vis-à-vis may include magnets, electromagnets, non-powered pads. In addition, the frame opposite can include a "squirrel cage".

In addition, according to the present invention, the windings forming the electrical phases of the machine can be divided into identical or different subsets.

The present invention will be better understood and other characteristics and advantages will become apparent on reading the following detailed description comprising embodiments given by way of illustration with reference to the appended figures, presented by way of non-limiting examples, which can be used to complete the understanding of this invention and the statement of its realization and, where appropriate, contribute to its definition, on which:

FIG. 1 is a detailed perspective view of an electromagnetic assembly with a polyphase structure of the prior art;

FIG. 2 represents a sectional view of an exemplary embodiment of an electromagnetic assembly with a polyphase structure according to the present invention, associated with an electromagnetic element of the magnet structure type, with an air gap to provide a device of the motor type. electric;

FIG. 3 is a perspective view of a yoke of the electromagnetic assembly with a polyphase structure of FIG. 2;

- Figure 4 is a sectional view of the cylinder head of Figure 3;

- Figure 5 is a perspective view of detail of the cylinder head of Figure 3;

- Figure 6 is a top view of a cylinder head of an electromagnetic assembly with a polyphase structure of the present invention according to an alternative embodiment relating to the arrangement of the pads;

FIG. 7a illustrates a perspective view of a geometric variant of a cylinder head of the polyphase electromagnetic assembly of the present invention, in a disc shape;

- Figure 7b is a partial sectional view of the cylinder head of Figure 7a associated with an electromagnetic element facing to provide an air gap;

FIG. 8 illustrates a perspective view of another example of an electromagnetic assembly of the present invention, the cylinder head being of generally parallelepipedal shape;

FIGS. 9a and 9b are perspective and sectional views, respectively, of another example of an electromagnetic assembly of the present invention, the cylinder head being of generally cylindrical shape;

FIG. 9c is an exploded view of the electromagnetic assembly of FIG. 9a; Figure 10 is a perspective view of a disc-shaped cylinder head of the polyphase electromagnetic assembly of the present invention according to a variant of the form of the pads;

FIGS. 11a to 11d illustrate examples of geometric shapes of the pads of the electromagnetic assembly of the present invention;

Fig. 12 is a sectional view of another embodiment of a yoke of the electromagnetic assembly of the present invention; and

FIG. 13 is a schematic view of coils associated with the cylinder head of FIG. 12.

FIG. 1 illustrates an electromagnetic assembly with a polyphase structure, in this case three-phase in the example presented in FIG. 1, of the prior art. Such an electromagnetic assembly comprises three annular electromagnetic heads C1, C2 and C3 respectively provided with P pads equidistant on their periphery. Each electromagnetic cylinder head C1, C2 and C3 is intended to correspond to a phase.

The electromagnetic heads C1, C2 and C3 are stacked along an axis z and are spaced to allow the integration of a winding (not shown) associated and arranged around the pads P of each electromagnetic cylinder head C1, C2 and C3 so that the coils are not touching at the polar faces F of the pads P. The polar faces F of the pads P are perpendicular to the z axis.

The electromagnetic heads C1, C2 and C3 are arranged between them so as to provide an angular offset between the pads P of two consecutive yokes C1 and C2, on the one hand, and C2 and C3, on the other hand. Thus arranged, along the z axis, the assembly has a length L1.

FIG. 2 presents an electromagnetic assembly with a polyphase structure 1 according to the present invention and a breech of which is illustrated in FIGS. 3 to 5. More specifically, FIG. 2 shows an electromagnetic assembly with a polyphase structure 1 according to the present invention in a configuration in which each phase is formed of a group each comprising seven teeth. The electromagnetic assembly with a multiphase structure 1 is intended to occupy a smaller volume than the electromagnetic assembly with a polyphase structure of the prior art shown in FIG. 1, in particular by providing a shorter length L along the z axis, while providing equivalent operating results. Such a benefit is obtained by the fact that the windings, in particular the heads of such windings, of the different phases are located in the same cylindrical zone, which eliminates any axial interference between them, and makes it possible to shorten the electromagnetic assembly.

It should be noted that, in FIGS. 2 and following relating to the electromagnetic assembly with polyphase structure 1 of the present invention, the structural and / or functional elements common to the different embodiments may have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties. The present invention is specific to the electromagnetic assembly with polyphase structure 1, intended to be used in particular as a stator in an electric motor, without however being limited to such an application. The electromagnetic assembly with polyphase structure 1 can also be used to form a DC electric machine, synchronous magnet, synchronous wound rotor, asynchronous squirrel cage rotor, asynchronous wound rotor, step by step ( variable reluctance), an alternator, a starter, a retarder, a position sensor, a speed sensor, an acceleration sensor, etc. The electromagnetic assembly with polyphase structure 1 of the present invention, for use, is, for example, a stator of generally annular shape and is associated on its outer periphery, as shown in FIG. 2, with a magnetic element 2 , advantageously a rotor 2, opposite and at a distance to provide a gap 3.

The magnetic element 2 consists, for example, of a plurality of pairs of magnets 20, 21 arranged, on the one hand, side-by-side and, on the other hand, facing and at a distance of the electromagnetic assembly with polyphase structure 1. Each pair of magnets 20, 21 corresponds to a magnetic pole.

According to the intended application, the magnetic element 2 facing the electromagnetic assembly 1 may be composed of non-powered pads, particularly in the context of a variable reluctance electrical machine, or a squirrel cage, particularly in the context of an asynchronous electric machine, or a coil supplied with direct current, in particular in the context of a synchronous electric machine, or a coil supplied with alternating current, in particular in the context of a machine electrical induction, or a coil shorted, especially in the context of an asynchronous electric machine. The magnets or the coil of the electromagnetic element 2 may be mounted on a smooth surface or arranged in grooves formed on the surface of the magnetic material body of the electromagnetic element 2.

The electromagnetic assembly with polyphase structure 1 comprises according to the present invention a single cylinder head 5 whose body is annular with a plurality of studs 50 protruding from one of the faces 5A of the yoke 5, said support surface 5A of the breech 5. In the embodiment shown, the support face 5A of the breech 5 is an external face. In addition, a winding 6 is associated with each of the pads 50.

FIGS. 3 and 4 illustrate an exemplary embodiment of the yoke 5 of FIG. 2. More particularly, FIG. 3 illustrates the exemplary embodiment of the yoke 5 of FIG. 2 in a configuration in which each phase is formed of two -Diameterally opposed groups each having three teeth

The yoke 5 is, in the exemplary embodiment, of annular shape with a median axis corresponding to the z axis which is perpendicular to a radial plane of the yoke 5. The studs 50 project from the outer face 5A. Alternatively, depending on the use, the studs 50 project from an inner face 5B, acting as a support face 5B, of the body of the yoke 5, as shown in the embodiment of FIG. 6.

The yoke 5 is preferably made of an assembly, in particular by riveting, of sheets of ferromagnetic material, stacked axially along the z axis.

The studs 50 constitute volumes protruding from the support face 5A or 5B of the cylinder head 5, and are separated by notches 51. As will be seen later, the studs 50 may have shape variants. On the other hand, for the same electromagnetic assembly according to the present invention, the studs 50 of the cylinder head 5 all preferably have the same shape.

In a particular embodiment, the studs 50 are one with the body of the cylinder head 5 because they are manufactured integrally with the body of the cylinder head 5 from pre-cut sheets or powder, in particular a ferromagnetic powder, agglomerated, in particular by pressing, sintering or any other method, whose circumference follows the geometry of the body of the yoke 5 and the studs 50. As a variant, after obtaining, the one-piece part comprising the studs 50 and the yoke 5 can be split into several identical or different sub-assemblies, in order to facilitate their assembly and the winding.

According to another alternative or alternative embodiment, all the pads 50 or a part of the pads 50 are removable. According to this embodiment, the pads 50 are associated with the body of the yoke 5 by interlocking with or without play and / or by bonding and / or by an interface element and securing.

The body of the yoke 5 preferably has receiving housings for housing a base of the studs 50, in particular in a form of mutual cooperation with the shape of the base of the studs 50, for example in the form of a tail. dove. The depth of the reception housing is preferably limited to 10 mm, and is in particular of the order of 1 mm. The removability of the pads 50 has the particular advantage of facilitating the insertion of the coil.

By an annular shape and a winding of the winding around the pads 50, the magnetic flux, when the coil 6 is supplied with current, is intended to be oriented substantially radially in the air gap 3. By radial direction is meant for the electromagnetic assembly according to the present invention, a direction corresponding to a radial direction with respect to the cylinder head 5.

The essential feature of the present invention relates in particular to the single yoke 5 of the electromagnetic assembly 1 and the arrangement of the studs 50 on the yoke 5 whose distribution will be detailed later. Compared with FIG. 1, the yoke 5 according to the present invention, as illustrated in FIGS. 2 to 4 and in the detail view of FIG. 5, provides an electromagnetic assembly with a polyphase structure in which the yoke 5 is unitary, unlike the plurality of C1 cylinder heads to C3 necessary in the realization of the prior art shown in Figure 1.

As shown in particular in FIG. 5, the yoke 5 of the present invention extends over a length L in the z direction smaller than the length L1 of the yoke according to the prior art of FIG. the breech (s). Thus, advantageously, for the same yoke circumference, the electromagnetic assembly with three-phase structure of the present invention has a length L of 20% less than the length L1 of the assembly of FIG. 1. According to the present invention, with reference to FIGS. 2 to 4, the pads 50 are arranged in several groups of pads, for example in three groups A, B and C, as shown diagrammatically in FIG. 4 by the dashed lines. Each group of pads A, B, C corresponds to an electrical phase.

In the embodiment shown, the electromagnetic assembly with three-phase structure has three groups to provide a three-phase structure. Each group of pads A, B, C is separated from the next group of adjacent pads by an intergroup distance D. The intergroup distance D is, in a particular configuration, distinct from an inter-pad distance E, or space E, separating two consecutive studs 50 of the same group of pads. The intergroup distance D and the interplanar distance E are understood by considering a median axis X of each pad in the direction perpendicular to the plane of the support surface 5A or 5B.

The inter-pad distance E between two pads 50 of the same group of pads is preferably identical. Alternatively, according to particular embodiments, the inter-plot distance E of the same group may be different.

In the example of Figures 2 to 5, each phase of the electromagnetic assembly with polyphase structure 1 corresponds to a single group of pads. For example, the electromagnetic assembly with structure three phase 1 of Figures 2 to 4, comprises twenty-one pads divided into three consecutive groups A, B and C of seven pads, each of groups A, B and C pads being intended to correspond to a phase.

The winding 6 of the electromagnetic assembly 1 is divided into distinct winding groups 60, 61, and 62, in particular three winding groups 60, 61, and 62, each associated respectively with each of the groups of pads, in particular three groups of pads. .

The cluster group configuration combined with an intergroup distance D distinct from the inter-pad distance E between two pads 50 of the same group of pads 50 makes it possible, when the winding groups 60 to 62 are electrically powered, to provide an offset. between the phases providing an electromagnetic assembly with a polyphase structure, here three-phase.

The electromagnetic assembly with a polyphase structure 1 as illustrated in the figures has a three-phase structure. Thus, on a single cylinder head 5, a polyphase structure is produced.

The electromagnetic assembly with a polyphase structure forms a one-piece assembly, that is to say with magnetic poles associated with a single yoke, unlike the prior art illustrated in FIG. 1, which has several yokes assembled consecutively along the axis z, each of the breeches forming with its pads a single phase.

The winding 6, respectively each winding group 60, 61, 62, associated with each group of pads 50 is an electrical conductor consisting of an electric wire or several electrical son grouped, being between them isolated or not, to form only one electric wire. The electric wire may have a solid or hollow section, may have a shaped section flat, hexagonal, round, square, rectangular, or any other shape, regular or non-regular. The electric wire is associated with each stud forming one or more turns (for example twenty-four turns in an embodiment).

The winding is associated with each pad by being wound around the stud, so-called nested manner, or is affixed alternately only against one of the polar faces of each pad according to an alternation of the polar faces at each consecutive pad, so-called corrugated as illustrated in FIGS. 9c and 11a.

Alternatively, it is possible to mix the types of corrugated and nested windings. Preferably, the coils 60, 61 and 62 are supplied separately by a polyphase power supply whose number of phases corresponds to the number of groups of pads and therefore of the phases of the electromagnetic assembly 1.

The coils 60, 61 and 62 are connected according to a star or triangle connection or zigzag or other.

In addition, advantageously, the input and the power supply output of each winding is respectively located at each of the end pads of each group of pads.

The yoke 5 is, in the example, Figures 2 to 5 of annular form. Depending on the applications, other non-annular head geometries may be used. By way of non-limiting examples, FIGS. 7a to 10 illustrate several variants.

Figures 7a and 7b illustrate a cylinder head 5 of discoidal shape with the pads 50 projecting from one of the faces of the yoke 5, said disc surfaces. The electromagnetic assembly is of three-phase structure in a distribution of three groups of pads A, B and C, each group comprising, according to the embodiment shown, three pads 50 and being associated with a respective winding 60 to 62 (not shown on the Figure 7b) wound around each stud to form a respective phase. The groups of pads A, B and C are separated from the intergroup distance D. The electromagnetic element 2, as shown in FIG. 7b, opposite has a magnetic element 2, in particular formed of magnets 20. The magnetic flux with the coils 60 to 62 associated is intended to be substantially axial, that is to say perpendicular to the support surface 5A of the cylinder head 5 of disc shape.

FIG. 8 illustrates an electromagnetic assembly 1 whose electromagnetic bolt 5 is of parallelepipedal shape. The electromagnetic assembly has a three-phase structure in a distribution of three groups A, B and C of parallelepipedal pads 50, each associated with a coil 60 to 62 to form the respective phases separated by an intergroup distance D. The pads 50 protrude by relative to the support surface 5A of the cylinder head 5 of rectangular shape. The electromagnetic assembly 1 is associated with an electromagnetic element 2 facing the studs 50 so as to form a gap 3. The magnetic flux is intended to be perpendicular to the support surface 5A of the cylinder head 5.

FIGS. 9a to 9c illustrate yet another embodiment of a cylinder-shaped yoke 5 for the electromagnetic assembly of the invention 1. The electromagnetic assembly 1 is associated with a magnetic element 2, in particular formed of magnets 20. According to the embodiment shown, the yoke 5 comprises eighteen magnetic poles distributed in three groups of studs 50 associated with three winding groups. 60 to 62 (not shown in FIGS. 9a and 9b) to respectively form three phases A, B and C separated from the intergroup distance D. The magnets are placed opposite studs 50 while leaving an air gap 3.

Advantageously, in particular to facilitate the winding of the windings around the studs 50, the yoke 5 is formed of two cylindrical portions 52 and 53 opposite assembled to each other integrally only after assembly of the windings. Each cylindrical portion 52, 53 of the yoke 5 comprises half of the total number of pads. For each cylindrical portion 52, 53 of the yoke 5, each stud 50 of a group is spaced apart, that is to say angularly offset, from the next stud by an offset distance G adapted to accommodate a stud of the part cylindrical breech 5 facing, as shown in Figure 9c.

Once the two parts 52 and 53 are assembled, the yoke 5 obtained constitutes a unitary assembly. In addition, the pads 50 are arranged to constitute an intergroup distance D distinct from the inter-plot distance E.

In a particular embodiment, the studs 50 are indented at their base providing a recess 54, recessed or projecting, for winding the coils 60 to 62, in particular undulating manner. Such a configuration of the pads 50 allows to gain volume parallel to the polar faces. Such a shape is usually referred to as "claw shape".

If the cylinder head can take different forms, the pads 50 may also have various shapes.

As non-limiting examples, the pads have:

a cylindrical shape with a circular section, as shown in FIG. 7a;

a cylindrical shape with a polygonal section, as shown in FIG. 10;

a claw shape, as shown in FIG. 9c and FIG. a mushroom shape, as shown in FIG.

- A divergent flared shape, as shown in Figure 1 1 c;

- A flared mushroom shape, as shown in Figure 1 1 d. Furthermore, a surface 55 of the pads, opposite to a surface of the plates integral with the support face 5A is intended to be facing the magnetic element 2, may have a shape that does not follow the shape of the line of the magnetic element 2 vis-à-vis, so as to provide a variable air gap. In particular, a surface shape, for example convex, can be envisaged.

The studs 50 and thus the yoke 5 have a length L in the direction perpendicular to the polar faces, in particular along the z axis for an annular or cylindrical yoke, or in the direction perpendicular to the direction of arrangement of the groups of studs.

The length L is adapted to the intended application. For example for an engine, this length will be a function of the maximum desired torque and the circumference of the cylinder head 5 when it is annular or cylindrical. In FIGS. 2 to 5, and 7a to 10, the exemplary embodiments of the electromagnetic assembly with polyphase structure 1 are such that each of the phases corresponds to a group of pads. The groups of pads are arranged consecutively relative to each other and preferably each have a coil distinct from the adjacent group. In an alternative embodiment illustrated in FIG. 12, each phase corresponds to the combination of at least two remote groups, that is to say two groups that do not follow each other consecutively, associated with the same separate winding of the winding of the others. groups. Remote groups associated with the same winding are called subgroups. The yoke 5b of FIG. 6 is equivalent to the yoke 5 of FIG. 12 in terms of distribution of the studs, the difference residing in that the studs of FIG. 6 are on the internal face 5B of the stud 5 while the studs of Figure 12 are on the outer face 5A of the yoke 5. The electromagnetic assembly with a polyphase structure 1 of FIG. 12 is associated with a magnetic element 2 opposite, in particular composed of magnets 20, arranged at a distance to provide an airgap 3.

The yoke 5 of the electromagnetic assembly with polyphase structure 1 is of annular shape, two subgroups of pads, in particular a pair of distant and non-adjacent groups, intended to form a phase with the associated winding are then arranged diametrically opposed.

For example, the yoke 5 comprises eighteen pads numbered P1 to P18 and divided into six subgroups A1, B1, C1, A2, B2, C2, each of three pads. The first phase corresponds to the two diametrically opposite subgroups A1 and A2 with the pads numbered P1, P2, P3, on the one hand, and P10, P1 1, P12, on the other hand. The second phase corresponds to the two diametrically opposed subgroups B1 and B2 with the pads P4, P5, P6, on the one hand, and P13, P14, P15, on the other hand. The third phase corresponds to the two diametrically opposite C1-C2 subgroups comprising the pads P7, P8, P9, on the one hand, and P16, P17, P18, on the other hand. The groups of pads, or subgroups, adjacent A1 to C2 are preferably equidistant from each other, that is to say that the intergroup distance is identical. To each pair of subgroups A1 and A2, B1 and B2, C1 and C2 is associated a respective winding 60, 61 and 62 to form the three phases respectively.

Figure 13 shows each of the windings 60 to 62 of the three phases. Each respective winding passes around the pads of each pair of subgroups.

According to a particular embodiment, the first winding 60 is associated with the pads P1, P2, P3, P10, P1 1 and P12, the input of the power supply being at the pad P1 and the output at the pad P12. The second winding 61 is associated with the pads P4, P5, P6, P13, P14, P15, the input of the power supply being at the pad P4 and the output at the pad P15. The third winding 62 is associated with the pads P7, P8, P9, P16, P17 and P18, the input of the power supply being at the pad P7 and the output at the pad P18. The current direction is symbolized by arrows in Figure 13.

The coils 60, 61 and 62 are supplied separately by a polyphase power supply whose number of phases corresponds to the number of pairs of subgroups of pads.

Whatever the embodiment, (each phase corresponding to each group of pads, each group taken consecutively, or each phase corresponding to at least two groups of non-consecutive pads called subgroups) an offset Θ between the phases is given in a preferred embodiment, by the following formula, which is expressed in electric angle,

for an odd number of phases:

o Θ = 180 Number of phases, if the number of pads per subgroup is odd

o θ = 360 Number of phases, if the number of teeth per subgroup is even

- for an even number of phases:

o θ = 180 Number of phases,

Each group, or subgroup, of pads preferably comprises an identical number of pads 50. Alternatively, according to specific exemplary embodiments, the groups of pads may comprise a different number of pads 50.

Finally, the number of magnetic poles Np of the magnetic element 2, in particular a rotor according to the exemplary embodiment presented, opposite the electromagnetic assembly with a multiphase structure 1 of the present invention is a function of the number of pads 50 of all electromagnetic polyphase structure 1 and the number of groups of pads.

The number of magnetic poles Np can be expressed in a preferred embodiment as follows:

Np = (Nphases ^* Nssgroups ^* Nplots-ssgroup) + kd where Nphases is the number of phases,

Nssgroups is the number of subgroups,

Nplots-ssgroupe is the number of pads per subgroup, and if the number of phases is even Kd = Nssgroups if the number of phases is odd and

if Nplots-ssgroup is odd, Kd = Nssgroups, or if Nplots-ssgroup is even, Kd = 2 ^* Nssgroups

Of course, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms and other variants that may be considered by those skilled in the art in the context of the present invention and in particular any combination of the different modes of operation described above, which can be taken separately or in combination.

Claims

1. Electromagnetic assembly with a polyphase structure (1) comprising

- a yoke (5) having an electromagnetic body, - a plurality of studs (50) spaced projecting from a support face (5A, 5B) of the yoke (5), and arranged consecutively along the periphery of the support face (5A, 5B) of the yoke (5), and

at least one winding (6) associated with the pads (50),

characterized in that

the cylinder head (5) is unique,

the plurality of studs (50) is arranged in at least two groups of studs (A, B, C), in which two studs (50) consecutive of the same group of studs (A, B, C) are spaced apart from each other; an interplanar distance (E) and each group of pads (A, B, C) is separated from the adjacent group of pads (A, B, C) by an intergroup distance (D) distinct from the distance between plot (E).

2. electromagnetic assembly with polyphase structure according to claim 1, characterized in that the body of the yoke (5) is annular, or cylindrical in one or two annular parts, or cylindrical abutments, or discoidal, or parallelepiped.

3. Electromagnetic assembly with polyphase structure according to claim 1 or 2, characterized in that it comprises several phases so that each phase corresponds

either to each of the groups of pads (A, B, C), the groups being considered consecutively, and a separate winding being associated with each group (60, 61, 62),

or at least two groups of remote blocks (A1, A2, B1, B2, C1, C2) associated with at least one and the same winding (60; 61; 62) separate from the winding of the other groups.

4. Electromagnetic assembly with polyphase structure according to any one of the preceding claims, characterized in that the intergroup distances (D) are identical throughout the cylinder head.

Electromagnetic assembly with polyphase structure according to the preceding claim, characterized in that each of the intergroup distances (E) is equal to an electrical angle corresponding to

- 180 Nphases, when the number of phases is odd and

- 360 Nphases, when the number of phases is even

where Nphases is the number of phases.

6. Electromagnetic assembly with polyphase structure according to any one of claims 3 to 5, characterized in that the number of subgroups of pads is preferably an even number and / or the number of groups corresponding to the number of phases is preferably one. odd number.

Electromagnetic assembly with polyphase structure according to any one of Claims 3 to 6, characterized in that it has a three-phase structure and comprises:

- three groups of pads (A, B, C), each group corresponding to a phase,

or three pairs of subgroups of pads (A1, A2, B1, B2, C1, C2), each pair of subgroups of pads (A1, A2, B1, B2;

C1, C2), corresponding to a phase and the two subgroups of each pair being arranged diametrically opposite and associated with the same winding.

Electromagnetic assembly with polyphase structure according to one of Claims 3 to 7, characterized in that each group of pads or subgroups has an identical number of pads.

Electromagnetic assembly with polyphase structure according to any one of Claims 3 to 8, characterized in that it comprises a coil (60, 61, 62) per group of pads or by combination of subgroups formed by one or more turns associated with each of the studs.

10. Electromagnetic assembly with polyphase structure according to any one of the preceding claims, characterized in that the winding (60, 61, 62) is realized

undulatingly passing from one pad to another, alternately passing from one pole face of a pad to an opposite pole face for the next pad, or

- nested way by completely surrounding each of the pads.

1 1. Electromagnetic assembly with polyphase structure according to any one of the preceding claims, characterized in that the winding (60, 61, 62) of each group or combination of subgroups for each phase is wedged angularly with respect to the electrical phase difference between the phases.

12. Electromagnetic assembly with polyphase structure according to any one of the preceding claims, characterized in that the studs (50) have various shapes such as a cylindrical shape with circular or polygonal base, or a mushroom shape, or a shape full flare preferably divergent towards the opposite of the support face, and / or a solid shape having on at least one of the polar faces (F) a recess (54).

Electromagnetic assembly with polyphase structure according to one of the preceding claims, characterized in that one or more studs (50) are releasably attached to the cylinder head.

14. Electromagnetic assembly with polyphase structure according to any one of the preceding claims, characterized in that each stud (50) has a surface (55) opposite to the support face of the yoke (5) and intended to be facing an air gap, having a convex shape.

15. Device comprising an electromagnetic assembly with a polyphase structure according to any preceding claim and an electromagnetic element (2) arranged vis-à-vis and at a distance to arrange between the electromagnetic element (2) and the electromagnetic assembly , a gap (3).